This invention relates to apparatus for sequentially receiving a series of articles to be conveyed from an infeed conveyor; separating each article by a preselected distance from the articles ahead of and behind it; and transferring the separated articles to an outfeed conveyor which delivers them to a further processing station.
The invention is particularly suited for use in indexing and transferring stacks of sheet material such as reams of paper received from an infeed conveyor of a sheeting machine which cuts and stacks the sheets, to an outfeed conveyor leading to a wrapping machine which wraps each ream for shipment. The prior art discloses some types of transferring and indexing apparatus for handling reams of paper in such a fashion which are highly complex in nature. To obtain separation of the reams as they are received from the infeed conveyor, the art teaches that one may accelerate the leading ream to a speed in excess of the infeed conveyor speed. This causes the stacked sheets of paper to shift or skew toward the trailing edge of the ream. Furthermore, the lower sheets of the ream frequently tend to wrinkle from the leading edges toward the trailing edge as the ream passes over prior art types accelerating rollers. The misalignment of the ream caused by such shifting enlarges the overall space occupied by the ream, which can interfere with operation of the outfeed conveyor and wrapping machine. Wrinkling of the lowermost sheets may cause similar interference and generally detracts from the quality of the wrapped product. Complicated prior art solutions to these problems have included arrays of reciprocating paddles located above an indexing and transfer station, which paddles contact the ream from the rear, causing some realignment of its sheets, and transfer it to an outfeed conveyor. The location of such paddle mechanisms above the path of the reams being conveyed has created problems with maintenance, in that the transfer station is not readily accessible in the event of a malfunction such as jamming with the outfeed conveyor.
Frequently in assembling a system comprising an infeed conveyor, an indexing and transferring station and an outfeed conveyor, it is not possible or practical due, say, to space limitations or the particular infeed and outfeed conveyor characteristics, to deliver articles to be transferred along a path which presents the articles ready for direct transfer to the outfeed conveyor. That is, the articles may be shifted to one side or another of the desired location for transfer. The prior art suggests a variety of manually adjustable guiding elements which may be used to correct such problems; however, known devices are too slow to use in a high speed conveying system and have not been found suitable for maintaining the alignment of the edges of stacks of sheet material such as paper reams.
An additional problem that has been encountered with known indexing and transfer stations concerns synchronizing operation of the infeed conveyor, the transfer station and the outfeed conveyor to provide continuous delivery of articles onto the outfeed conveyor. Usually, the outfeed conveyor in prior art transfer systems is operating at a slightly higher rate of speed than the product on the infeed conveyor. The transfer station must be able to stop and wait until the outfeed conveyor is in a position to receive the product. Additionally, the outfeed conveyor may stop for a variety of reasons, at which time the transfer station must stop and wait, while providing a control for the infeed conveyor.
This problem is acute with prior art belt transfer stations which anticipate stopping of the outfeed conveyor, thus requiring close timing to avoid jamming and similar problems, particularly with outfeed conveyors having alignment paddles for guiding the articles being conveyed.
An object of this invention is to provide an article indexing and transferring system which will separate articles to be conveyed and deliver them continuously to an outfeed conveyor.
A further object of this invention is to provide means in such an apparatus for aligning the vertical edges of stacks of sheet material while such stacks are being transferred.
Still another object of the invention is to provide such an apparatus in which the articles being conveyed, and the elements of the apparatus contacting the articles to index and transfer them, are readily accessible from above without requiring partial disassembly of the apparatus.
Another object of the invention is to provide means for indexing or separating reams of paper without wrinkling the lowermost sheets of the ream.
Yet another object of this invention is to provide means for automatically shifting articles received from an infeed conveyor to a location properly situated for direct transfer to an outfeed conveyor.
A still further object of this invention is to provide such an apparatus in which the speed of indexing and transfer may be varied as required to suit a particular outfeed conveying system.
The above objects are considered exemplary of the purposes of this invention. Although those skilled in the art may perceive additional objects of the disclosed apparatus the failure to mention such objects here is not to be taken in any way to limit the scope of the disclosed invention as defined in the claims hereafter presented.